It is often desirable to package sheet materials in roll form, and to provide a cutting mechanism for severing the sheets into desired lengths; depending upon intended use. It is quite common to package such rolls in cartons that are intended to be disposed of after the rolls have been depleted. Obviously any cutting mechanism employed as part of such a carton must be sufficiently economical to manufacture to justify its disposal along with the package. Although inexpensive mechanisms, such as serrated cutting bars, are known, they generally are not capable of accurately and easily cutting strong flexible sheet materials of the type that tend to stretch or flex as they are being subjected to a cutting force. Moreover, in the case of serrated cutting bars, it is quite easy for a person handling the package to inadvertently cut himself.
Although other types of cutters have been disclosed for use on boxes or cartons in which roll materials are packaged, a need does exist for improved low cost cutters which can be easily fabricated, which are reliable and safe in operation, and which are capable of cutting a wide variety of different sheet materials; particularly those that are strong, stretchable and flexible.
One prior art approach to cutting flexible sheet materials is to include the cutting element on a moveable assembly that has rotatable elements, such as wheels, to press the sheet material against a stationary plate or track for locally immobilizing the material as it is being cut. These devices have been found to work quite well; however, they are believed to be too expensive for the limited use encountered on packages of disposable products. The following patents disclose representative devices of the type employing rotatable elements as part of the cutter: U.S. Pat. Nos. 1,745,476 (Cohn); 2,503,353 (Pugh); 3,277,760 (Keene et al); 3,463,040 (Pouilloux) and 3,791,246 (Lazickas).
A different type of cutting assembly employs a clamping arrangement that is operated independently of a sliding cutter to immobilize the sheet prior to the cutting operation. In this type of device the clamping action is achieved between a stationary surface and a hinged, moveable surface. The use of relatively moveable clamping elements increases the overall cost and complexity of the cutting assembly, as compared to assemblies in which separate clamping bars, independent of the cutter slide, are not utilized. The following patents disclose representative devices of the type employing moveable clamping elements: U.S. Pat. Nos. 3,142,217 and 3,370,497 (Busse) and 3,222,972 (Fulton).
A fairly simple cutting assembly is disclosed in U.S. Pat. No. Re 22,565, issued to Gillanders et al. This device is designed for use in cutting adhesive tape, and employs a cutter knife that is adapted to move along an elongated slot in a cylindrical bore. A handle is secured to the upper end of the knife to aid in moving the knife along the slot, and the handle is provided with laterally spaced-apart wings to prevent accidental contact of the blade by the user. The wings also are employed to press the adhesive surface of the tape against a bead adjacent the slot to adhesively attach the tape to said bead. Although this cutter may be suitable for immobilizing adhesive tape by pressing its adhesive surface against the guide in which the knife is slid, there is no mechanism, either provided or suggested, for adequately immobilizing non-adhesive sheet materials during a cutting operation.
An improvement over the Gillanders et al construction has been invented by Balbir Singh and Ernest M. Pinhak, and is disclosed in co-pending U.S. Pat. application Ser. No. 959,359, entitled "Cutting Assembly", and filed on even date herewith. In the Singh et al assembly a top surface of a track is roughened, and a cutter slide, moveable in the track, includes an extremely smooth stationary lower surface overlying the roughened track surface to press the sheet material to be cut against said roughened track surface as the cutting operation is performed. Although this type of system represents a very economical approach to immobilizing non-adhesive sheet materials during a cutting operation, it may not provide the desired degree of immobilization and tensioning for reliably cutting extremely strong and stretchable sheets.
Applicants' cutting assembly is an improvement over that disclosed in the Singh et al patent application.
In order to economically manufacture the cutting assembly it is highly desirable to form it of a minimum number of components. To this end it is highly desirable to be able to form the elongate track as a single unit, and in a form that will permit the cutter slide to be mounted and retained within an interior compartment thereof.
It is known to mold two sections of an article as a single unit with a hinge section between them to permit the sections to be moved together to form a closed interior compartment, as is exemplified in U.S. Pat. No. 3,834,007, issued to Lambiris. In order to mold an elongate track or article having a split upper wall capable of defining a slot that communicates with an interior compartment, the split upper wall sections should initially be moldable in an opened position to permit insertion of the cutter slide. This type of forming technique is not suggested by Lambiris. Thereafter, the upper wall sections should be moveable into, and retained in the position they assume in the final track configuration to both trap the cutter slide in the interior compartment and form the slot in which the cutter slide is moveable. Clearly this type of forming technique is not suggested by Lambiris.
The instant invention relates to a simple and reliable cutting assembly, and to a unique method that can be employed to form, as a one-piece unit, the track of the cutting assembly.